The present invention relates to irrigation systems for controlling the operation of a number of control valves each of which in turn controls the flow of water in a corresponding branch pipe leading from a common supply pipe.
Such irrigation systems are well known, however, the systems suffer from a number of disadvantages. The most significant disadvantage is that hitherto each control valve has been connected to a corresponding pair of wires which extend from a centralized location to the location of the control valve. For electrical safety reasons, these wires carry low voltage electrical power used to switch on and off the control valve. As a consequence, the wires must be of a substantial diameter in order to carry the necessary current required to operate the valve. As the number of control valves increases, so the length and number of the pairs of wires also correspondingly increases. This results in a substantial burden both in terms of the cost of supplying the wires which are made from expensive copper, and also in terms of laying the wires in or on the ground to be irrigated and the valuable space occupied by such wires.